poorness vs inadequacy

poorness and inadequacy both are nouns.

Word	Noun	Adjective	Verb	Adverb
poorness	Yes	No	No	No
inadequacy	Yes	No	No	No

As nouns, inadequacy is a hypernym of poorness; that is, inadequacy is a word with a broader meaning than poorness:

Other hypernyms of poorness include deficiency, insufficiency.

poorness (noun)	inadequacy (noun)
the quality of being poorly made or maintained	unsatisfactoriness by virtue of being inadequate
less than adequate	lack of an adequate quantity or number
the quality of being meager	a lack of competence
the state of having little or no money and few or no material possessions